Confucius left no state and no army, and for three centuries after his death his followers were one philosophical school among several competing for a ruler's ear. Dong Zhongshu is the reason that stopped being true. Advising Emperor Wu in a set of famous court examinations around 134 BCE, he argued that a single, exclusive orthodoxy, Confucian learning as taught through the Five Classics, should organize the empire's scholarship and its officialdom, displacing the Legalist and Huang-Lao Daoist currents that had shaped early Han government.
The philosophy he offered to back that claim was not the ethics of the Analects alone but a full cosmology. Heaven, he argued, is not indifferent to human affairs: it responds to a ruler's conduct through the correlative system of yin and yang and the Five Phases, registering misgovernment as eclipses, floods, comets and other portents. This gave Confucian officials something no purely ethical doctrine could, a standing, cosmically sanctioned language in which to criticize an emperor to his face, "portent-reading" that Han and later dynasties took seriously enough to prompt genuine policy reversals. The Imperial Academy he helped found trained officials in the classics he had canonized, and for the better part of two thousand years, until the fall of the imperial system in 1912, some version of Dong Zhongshu's settlement, Confucian classical learning as the entrance exam to government, remained in force.